Straps are necessary component parts of diving masks used for both swimming or diving. These straps are used mainly to fasten the diving mask to the user's face, thus preventing water from entering the mask.
The tightness of strap determines whether or not: water enters the inside portion of the diving mask, the diving mask shifts in position or falls off easily during movement, and or the user's comfort level. With the straps set too loosely, the mask is likely to leak water, and shift positions or fall off easily. While, when the straps are set too tight, the user is likely to feel uncomfortable.
There are currently, many different types of head-wear, ranging from headbands, helmets, all the way to diving and swimming goggles. However, the most important requirement of all the differing head-wears is that it must be adaptable to the varying head sizes of different users. The head-wear must also be able to accommodate for the user's aesthetic feel, and fulfill the function for which it was bought.
For example, the traditional diving mask, it's strap adjusters are located in both sides of the diving mask. In order for the user to adjust the tightness of the strap the user needs to adjust the strap on one side at a time. However, by adjusting the mask from one side at a time, the original placement is lost, thus making optimal adjustment much harder to achieve. The added volume created by the traditional 2 side adjustment buckles also presents itself as an additional drawback. With a greater volume, the user will have a lesser field of vision, and be more troubled with the diving mask's size. With the best adjuster however, the user is able to adjust both sides of the mask at one time, thus allowing easier optimal fitting. The mask is also allowed to have lesser volume, which is another benefit towards the user.